Reliability and validity of the Unified Classification System for postoperative periprosthetic femoral fractures around cemented polished taper-slip stems

Aims This aim of this study was to assess the reliability and validity Unified Classification System (UCS) for postoperative periprosthetic femoral fractures (PFFs) around cemented polished taper-slip (PTS) stems. Methods Radiographs 71 patients with a PFF admitted consecutively at two centres between 25 February 2012 19 May 2020 were collated by an independent investigator. Six observers (three hip consultants three trainees) familiarized UCS. Each classified on separate occasions, mean time assessments 22.7 days (16 29). Interobserver more than assessed using percentage agreement Fleiss’ kappa statistic. Intraobserver calculated Cohen Validity tested surgically managed UCS type B PFFs where stem stability documented in operation notes (n = 50). statistic radiological assessment intraoperative findings. Kappa statistics interpreted Landis Koch criteria. All six blinded radiographs. Results 58.5% overall value 0.442 (moderate agreement). Lowest values seen (0.095 0.360). The intraobserver 0.672 (0.447 0.867), indicating substantial agreement. 65.7% 0.300 (0.160 0.4400) only fair Conclusion demonstrates that is unsatisfactory classification PTS stems, it has considerably lower previously described other types. Radiological loosening presence poorly defined formal testing recommended. Cite article: Bone Joint J 2021;103-B(8):1339–1344.